The age related changes of nitric oxide and apoptosis in experiment

The process of aging and senescence, associated with a decline in several organ functions, ultimately takes away independence and reduces quality of life. Programmed cell death or apoptosis is highly involved throughout the aging process, from early developmental changes to senescent declines in function. It is now widely accepted that the age-related downregulation of apoptosis does occur in both, the mitotic and postmitotic organs, such as liver and heart. Several studies have established that nitric oxide (NO) and its reaction products can either promote or prevent apoptosis in a multitude of settings. The aim of present study was to reveal a possible correlation between the production of nitric oxide (NO) and apoptosis in white mice during aging. 36 white mice were used. According to the age the animals were distributed in three groups (juveniles, adults, senescents). The animals were anesthetized with ether narcosis and were sacrificed by the method of decapitation. Heart and liver were removed. Number of apoptotic nuclei were counted by a Becton Dickinson (Mountain Vieu, CA) FACScan flow cytometer. Concentration of NO in samples was measured, on ESR spectrometer RE 1307 (Chernogolovka, Russia). Statistical analyses was performed using Student t test for independent samples. Probability (P) values of <0,05 were considered to be significant. All data are expressed as mean (standard deviation). According to received data the age-related activity of NO production is different in different organs. In liver NO production was significantly high in juvenile and aged mice, whereas in the heart this parameter significantly decreases during aging. The strict correlation was revealed in age-related changes of apoptotic activity and NO production in both liver and myocardium. In the liver the age-related decrease and further increase of NO production correlates with similar changes in apoptotic activity of hepatocytes. Whereas in the myocardium the age-related decrease of NO production results in increase of apoptotic activity. Thus, we can consider, that the level of NO has different influence on the apoptotic process in different organs during aging. The high levels of NO might have a proapoptotic effect in liver and antiapoptotic - in myocardium.